This invention relates to a fuel flow control valve in the fuel supply line between the fuel tank and an automobile engine driven fuel pump and has for a specific object the provision of improved fuel flow control means in the fuel supply line to prevent fuel leakage from the tank via the fuel line in the event of an accident, as for example where the automobile is rolled over or suddenly tilted to such an angle that fuel would otherwise flow by gravity through the fuel line from the tank.
Invariably in consequence of such an accident, the engine stalls. Another object therefore is to provide such a flow control valve which is normally closed to prevent fuel leakage from the fuel tank when the engine is not operating, but which opens automatically by operation of the fuel pump to enable starting of the engine by cranking, without requiring a resetting of the control valve or other structure, and remains open when the engine is operating.
Preferably the pump comprises a fuel pumping chamber operative to effect alternate fuel pumping and fuel vacuum cycles, and an air pumping chamber operative to effect concurrent air vacuum and air pumping cycles respectively. The chambers are connected with the control valve to maintain the latter open in response to either or both the air pumping and fuel vacuum cycles. The fuel pumping cycle has no effect in opening the control valve, which is thus practically immune to vapor lock conditions in the pump.
Other objects are to provide a flow control valve of the above character which is urged to its closed position by a fuel pressure head in the fuel supply line greater than atmospheric, and to provide means cooperable with the fuel pump and valve to accumulate small quantities of air pumped during the air pumping strokes to maintain the valve open uninterruptedly during cyclic operation of the pump, but which enables rapid closing of the valve when the pump stops.
Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.